Lithium Powered LED Headband Lens Light
by solara70 in Circuits > LEDs
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Lithium Powered LED Headband Lens Light
These headband lights are great for detailed work requiring a magnified light source and lens.
I purchased mines from amazon for under £20.
Its ideal for inspecting motherboards, SMT components, tracks etc, without the use of a microscope. Enables you to keep your hands free and retain a good depth of working vision.
It runs on 3 AAA batteries. Which can be heavy on the nose and can also drain cheap batteries quite fast. I suspect the light module is just 2 white leds in parallel with a resistor.
It goes dim at about 3v, compared to full brightness at 4.5v for a new set of batteries. I did some trsts and at 4.5v it consumes 12mA, light output and current drops gradually with voltage switching off at about 2v.
Its another good candidate for lithium power, with undervoltage protection. However space is tight in the AAA battery compartment. An 18650 wont fit internally. Time to try something smaller, which still packs a punch.
I purchased mines from amazon for under £20.
Its ideal for inspecting motherboards, SMT components, tracks etc, without the use of a microscope. Enables you to keep your hands free and retain a good depth of working vision.
It runs on 3 AAA batteries. Which can be heavy on the nose and can also drain cheap batteries quite fast. I suspect the light module is just 2 white leds in parallel with a resistor.
It goes dim at about 3v, compared to full brightness at 4.5v for a new set of batteries. I did some trsts and at 4.5v it consumes 12mA, light output and current drops gradually with voltage switching off at about 2v.
Its another good candidate for lithium power, with undervoltage protection. However space is tight in the AAA battery compartment. An 18650 wont fit internally. Time to try something smaller, which still packs a punch.
Supplies
14500 lithium battery
Tp4056 usb charger
Cutters pliers
Soldering iron
Tp4056 usb charger
Cutters pliers
Soldering iron
Make Some Space
Remove the battery spring terminals.
Using cutters snip any extended bits of plastic to make some space for an 14500 lithium cell.
The cells i bought came with solder tags.
The 14500 cell wedges in snug.
Solder up positive and negative terninals to existing wiring, and in parallel with a twin male/female mini plug.
You could make the battery removable using the male/female connector setup, but I prefer to recharge in situ, rather than swap out batteries.
It would be a very tight (unsafe?) squeeze to contain an internal tp4056 usb charger, so i kept it in an external module for now. You could of course mount the board externallly above or below the battery with hot glue.
Apparently the battery is labelled with an internal "re/discharging protestion" circuit. I dont trust it as it was mis-spelt! Short circuiting the battery showed the current drop from 10 amps to about 5 amps then hold at 3.7v. The positive end of the battery did get hot so i assume there is a protection circuit there. I am not sure if it will cut off when it goes undervoltage to protect the battery. Time will tell, should i forget to switch it off.
I have an existing external tp4056 charger which i made in my "repurposing mobile phone batts" instructable.
Using cutters snip any extended bits of plastic to make some space for an 14500 lithium cell.
The cells i bought came with solder tags.
The 14500 cell wedges in snug.
Solder up positive and negative terninals to existing wiring, and in parallel with a twin male/female mini plug.
You could make the battery removable using the male/female connector setup, but I prefer to recharge in situ, rather than swap out batteries.
It would be a very tight (unsafe?) squeeze to contain an internal tp4056 usb charger, so i kept it in an external module for now. You could of course mount the board externallly above or below the battery with hot glue.
Apparently the battery is labelled with an internal "re/discharging protestion" circuit. I dont trust it as it was mis-spelt! Short circuiting the battery showed the current drop from 10 amps to about 5 amps then hold at 3.7v. The positive end of the battery did get hot so i assume there is a protection circuit there. I am not sure if it will cut off when it goes undervoltage to protect the battery. Time will tell, should i forget to switch it off.
I have an existing external tp4056 charger which i made in my "repurposing mobile phone batts" instructable.
Charge and Use
Connect up the usb tp4056 charger, wait for it to turn blue, and its fully charged at about 4.2v.
tuck in the battery charging fly lead, and
Snap back in the battery cover.
Use it!
Its so much lighter and brighter than on alkaline AAA batteries.
The battery "says" its 2300mah. Lets say its approx half that at 1200mAh. At 10ma consumption, a full charge should give 120 hours (5 days) of use!
A recommended mod if you have a pair.
tuck in the battery charging fly lead, and
Snap back in the battery cover.
Use it!
Its so much lighter and brighter than on alkaline AAA batteries.
The battery "says" its 2300mah. Lets say its approx half that at 1200mAh. At 10ma consumption, a full charge should give 120 hours (5 days) of use!
A recommended mod if you have a pair.
Tp4056 Protection and Usb Port Onboard
I was a bit wary of undervoltage damage to the battery as I dont believe the battery provided this.
Rather than risk damaging the battery, by accidentally leaving it on , and it go flat. I made the mod to add the tp4056 on board.
Dremel, wireup and hot glue.
Battery is soldered to bat+ bat -
Out + out - goes to led red black wires.
Rather than risk damaging the battery, by accidentally leaving it on , and it go flat. I made the mod to add the tp4056 on board.
Dremel, wireup and hot glue.
Battery is soldered to bat+ bat -
Out + out - goes to led red black wires.